Bombay blood in the parent or children. Bombay phenomenon - what is it? Significance of high level in determining other diseases
As you know, there are four main blood groups in humans. The first, second and third are quite common, the fourth is not so widespread. This classification is based on the content of so-called agglutinogens in the blood - antigens responsible for the formation of antibodies. The second blood group contains antigen A, the third contains antigen B, the fourth contains both of these antigens, and the first contains no antigens A and B, but there is a “primary” antigen H, which, among other things, serves as a “building material” for the production of antigens contained in the second, third and fourth blood groups.
Blood type is most often determined by heredity, for example, if the parents have the second and third groups, the child can have any of the four, if the father and mother have the first group, their children will also have the first, and if, say, the parents have the fourth and the first, the child will have either the second or the third. However, in some cases, children are born with a blood type that, according to the rules of inheritance, they cannot have - this phenomenon is called the Bombay phenomenon, or Bombay blood.
IN Bombay blood there are no A and B antigens, so it is often confused with the first group, but it also does not contain the H antigen, which can become a problem, for example, when determining paternity - after all, the child does not have a single antigen in his blood that his parents have .
The Bombay phenomenon was discovered in 1952 in India, where, according to statistics, 0.01% of the population have “special” blood; in Europe, Bombay blood is even less common - approximately 0.0001% of the population.
A rare blood type does not cause its owner any problems, except for one thing - if he suddenly needs a blood transfusion, then only the same Bombay blood can be used, and this blood can be transfused to a person with any group without any consequences.
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This article discusses the choice of medication to treat hypertension in elderly patients. Older people suffering from hypertension are a category of patients to which doctors have a special attitude. Practice has shown that medicinal reduction blood pressure elderly people have their own characteristics, and further you will find out what they are.
The standard approach, which is used for patients aged 30 to 60 years, may not be effective for people retirement age. However, this in no way means that elderly hypertensive patients should give up on themselves and abandon all medical care. Effective treatment hypertension in older people is real! For this, the competent actions of the doctor, the love of life of the patient himself, as well as the support that his relatives can provide are important.
- The best way to recover from hypertension (quickly, easily, healthy, without “chemical” drugs and dietary supplements)
- Hypertonic disease - folk way recover from it at stages 1 and 2
- Causes of hypertension and how to eliminate them. Tests for hypertension
- Effective treatment of hypertension without drugs
If an older person with hypertension has no complications, it is recommended to start treatment with a thiazide diuretic, which is also prescribed for younger people with a similar condition. However, an elderly person should start taking the drug at half the normal dose. For most older people, the optimal dosage is 12.5 mg dichlorothiazide. It is necessary to increase the dosage to 50 mg in extremely rare cases. If 12.5 mg tablets are not available, break the 25 mg tablet into two halves.
Activity pharmacological agents in reducing blood pressure varies depending on the age of the patients. This was confirmed in a 1991 study. In particular, it was possible to show that the effectiveness of thiazide diuretics is higher in people 55 years of age and older than in younger patients. Therefore, diuretics in low doses are especially indicated for the treatment of elderly patients suffering from hypertension. Although older people often have high levels of cholesterol and other harmful fats in the blood (such as triglycerides), this does not necessarily prevent them from taking small doses of a thiazide diuretic (which raises blood cholesterol in high doses). It appears that taking a thiazide diuretic in low doses will have little effect on cholesterol levels.
If in the body low level potassium or sodium, or high calcium levels, a thiazide diuretic can be taken in combination with a potassium-sparing drug. It is not recommended for older people to take extra potassium because it causes two problems at their age: they have difficulty taking pills, and their kidneys cannot remove the extra potassium from the body.
Calcium antagonists for the treatment of hypertension in the elderly
Calcium antagonists from the dihydropyridine subclass (nifedipine and its analogues), together with thiazide diuretics, are very suitable medications for hypertension in elderly patients. Dihydropyridine calcium antagonists have a moderate diuretic effect, which does not lead to a further decrease in the volume of circulating blood plasma, which is generally characteristic of old people and is usually enhanced by diuretics. Calcium antagonists are active in the low-renin form of hypertension and support renal and cerebral blood flow. There are also indications that drugs from this class can improve the properties of the aortic elastic chamber of the heart, thereby helping to reduce systolic pressure, which is especially important for elderly patients.
Another study in 1998 confirmed the effectiveness of calcium antagonists in patients with isolated systolic hypertension. Patients were prescribed nitrendipine as monotherapy or in combination with enalapril or hypothiazide (12.5-25 mg per day). This significantly reduced the risk cardiovascular complications: sudden death- by 26%, stroke rates - by 44%, overall mortality - by 42%. There is no doubt that diuretics, as well as calcium antagonists, improve the prognosis for patients with isolated systolic hypertension. Calcium antagonists are not only blood pressure medications, but also effective means from angina pectoris. True, patients in whom hypertension is combined with coronary disease heart, you should take these drugs not for too long and preferably with breaks (pauses).
We would like to draw the attention of the readers of this article (this is for doctors, patients - do not self-medicate!) to enough high efficiency calcium antagonist diltiazem in elderly patients with hypertension. Particularly good results can be obtained by combining diltiazem with perindopril. It is appropriate to consider one more important question. It has been suggested that calcium antagonists promote the development oncological diseases in patients over 65 years of age. In a large-scale study that lasted 3 years, these assumptions were not confirmed.
Treatment of hypertension in elderly patients with beta blockers
If the patient cannot take a thiazide diuretic or for some reason the drug is not suitable for the patient, it is recommended to take a beta blocker. Beta blockers are less effective than thiazide diuretics, and they also have more side effects.
Beta blockers are less effective in treating older people with heart failure, asthma, chronic diseases lungs or obstructive blood vessel disease. However, if a person has previously taken a thiazide diuretic, but the blood pressure has not normalized, taking an additional beta blocker will often help normalize the blood pressure.
Other drugs for the treatment of hypertension in elderly patients
ACE inhibitors and angiotensin II receptor blockers are not as effective as thiazide diuretics or beta blockers, but they can be used in cases where thiazide diuretics or beta blockers are not suitable for some reason (for example, in case of allergies to medications ). According to the results of the American study VACS (Veterans Affairs Study), the activity of captopril in patients 60 years of age and older did not exceed 54.5%. ACE inhibitors are more indicated for treatment in patients suffering from diabetes mellitus. The problem with ACE inhibitors and angiotensin II receptor blockers is that while they all lower blood pressure, they are less effective at preventing hypertension-related illnesses and deaths.
Joint reception ACE inhibitor and diuretics may contribute to an excessive decrease in blood pressure. A few days before starting an ACE inhibitor, you should stop taking the diuretic. The dose of an ACE inhibitor for an elderly person should be reduced. Regular daily dose is 10 mg, but an older person needs to reduce it to 5 mg.
Other drugs that act on the brain include medications such as methyldopa, clonidine (clonidine) and guanabenz, as well as alpha-adrenergic blockers. These are powerful medications that cause drowsiness and depression, as well as a decrease in blood pressure when standing. They are prescribed to older people with caution. Alpha-1-blockers (doxazine, etc.) remain the drugs of choice for the treatment of hypertension in patients suffering from benign hyperplasia (adenoma) prostate gland. Agonists of central alpha-2-adrenergic receptors (clonidine) cause weakness, drowsiness, and mental depression in elderly patients with hypertension. In addition, when treated with clonidine (clonidine), “rebound” hypertension often occurs and, apparently, there is no reversal of left ventricular hypertrophy of the heart.
Special cases
- The use of beta blockers is advisable in cases where an elderly hypertensive person also experiences chest pain caused by coronary atherosclerosis.
- ACE inhibitors tend to prolong life in people with congestive heart failure, so these are the drugs that should be given to people with heart attacks and hypertension.
- ACE inhibitors and angiotensin II receptor blockers are especially useful for older people with increased blood pressure who have kidney problems, often associated with diabetes.
What medications for hypertension should be used in elderly patients, depending on the presence of concomitant diseases
This information is provided for doctors! Patients - please do not prescribe hypertension pills on your own! Contact a qualified doctor!
- How can an elderly person take medications for hypertension correctly?
- Isolated systolic hypertension in the elderly
- Pseudohypertension in elderly patients
- Postural hypertension in the elderly
Hematocrit is increased or decreased: what does it mean and why does it happen?
Norm in children and adult men and women
You can find out about hematocrit indicators after passing general analysis blood (displayed as a percentage by the NST indicator). Healthy condition the body depends on the patient’s age and gender.
Age group - children:
- newborns - 35-65
- up to 12 months - 32-40
- from one to eleven years - 32-41
Teenagers (12-17 years):
- girls - 35-45
- boys - 34-44
Age group - adults:
- women from 18 to 45 - 39-50
- men from 18 to 45 years old - 34-45
- age of a man over 45 - 40-50
- woman's age over 45 - 35-46
Hematocrit concentration variations in adults between 30% and 35% will require observation in the clinic and recommendations for dietary changes to increase the intake of meat, liver, fruits and leafy vegetables.
29% and 24% - a pre-painful condition, eliminated by taking medications with iron, vitamin B and folic acid.
Increased hematocrit number
High hematocrit concentrations result in thicker blood, which increases the risk of thrombosis. An increase in hematocrit in the blood can occur due to poor lifestyle and other reasons:
- Dehydration. Drinking less fluid than normal leads to moisture deficiency, and correspondingly reduced plasma concentrations change blood parameters. Active dehydration occurs after diarrhea, bouts of vomiting, overheating, or too active physical activity that provokes profuse sweating.
- Hypoxia. Chronic lack of oxygen leads to the active emergence of new blood cells- red blood cells, which serve to transport oxygen to the tissues of various organs. Hypoxia is typical for people for a long time those in stuffy spaces, smokers and patients with diabetes.
- Mountain conditions. Directly related to hypoxia caused by being in mountainous areas. Low content oxygen in rarefied air leads to an unpleasant effect - increased production of red blood cells. Climbers and people forced by profession to be at heights are recommended to take oxygen tanks with them.
Indicator in the diagnosis of cardiovascular diseases
Bringing the number of red blood cells in the blood to normal is extremely important for heart patients.
Blockage of the lumen of blood vessels, formation of blood clots in small and large arteries obstruct arterial flow, dangerously loading the heart muscle. A weak heart begins to work harder, which leads to an increased risk of myocardial infarction.
The resulting arterial thrombosis (due to an increase in the number of platelets) initially leads to the appearance of the ischemic stage, followed by the process of tissue death through induced oxygen starvation.
Heart failure, which results in fluid accumulation, also results in identical test results. The critical hematocrit content is considered to be more than 50-55% (hospitalization required).
Significance of high level in determining other diseases
Kidney problems, primarily hydronephrosis and polycystic disease, lead to an increase in the quantitative value of red blood cells. A similar effect is achieved by uncontrolled (long-term) use of corticosteroid and diuretic drugs that stimulate the removal of fluid from the body.
Other states:
- suffered stress;
- injuries skin(over 10%);
- gastrointestinal diseases;
- erythrocytosis;
- bone marrow diseases.
Pulmonary diseases - bronchial asthma, obstructive bronchitis- make it difficult to supply oxygen to the lungs, so the process of hematopoiesis intensifies.
During pregnancy, late toxicosis disrupts the functioning of the kidneys, which increases the content of red blood cells in the blood. Blood thickening is observed closer to childbirth - in the second half of pregnancy: this is how nature prepares a woman for childbirth, which is often associated with heavy blood loss.
Reduced content
Red blood cells participate in the construction of the body, feeding it with amino acids and carrying out gas exchange. A decrease in the number of blood cells can lead to various dysfunctions and problematic conditions. Reduced level should alert you. Let's consider possible reasons decrease in hematocrit in the blood.
Heart pathologies
Any heart defects are more difficult to treat if the number of red blood cells is low, since cardiac problems are aggravated by a difficult supply of oxygen to the tissues of the heart. Unlike increased hematocrit, a reduced red blood cell count does not have such a detrimental effect on the heart.
Red blood cell to hemoglobin ratio:
- initial stage - 3.9-3/110-89
- average - 3-2.5/89-50
- severe - less than 1.5/less than 40
These indicators also determine the degree of anemia.
Low percentage for other reasons
A low red blood cell count is often associated with general malaise, constant desire lie down to rest, general loss of strength. The most common disease when the hematocrit in the blood is reduced is anemia caused by a decrease in the amount of iron.
Reasons for the decrease in red blood cells:
- blood loss;
- overhydration;
- primary tumors;
- dysbacteriosis;
- smoking and alcohol.
Long-term use of medications can also cause blood thinning; for example, frequent use of aspirin leads to exactly this consequence.
An unfavorable factor is prolonged bed rest, as well as high water consumption (also caused by renal failure and intravenous infusions).
Transferred infectious diseases and chronic inflammatory processes equally have a lowering effect on the number of red elements in the blood. Not only visible bleeding - caused by fractures and injuries - is dangerous, but also hidden bleeding, primarily internal.
Liver cirrhosis, tumor disintegration, uterine fibroma, varicose veins esophageal veins, thallasemia are frequent companions of invisible blood loss.
Children's tests - what to prepare for
Newborns often exhibit hyperprolactinemia, indicating an increase in protein in the blood plasma. It is caused by feeding the child milk from a goat or cow (situation: the mother does not have access to breast-feeding) with a high protein content. To increase the tendency for blood to thicken, you should buy milk with less protein.
At the age of 3 years there is a decrease mental abilities, fatigue, shortness of breath, pale skin color and rapid heartbeat. Among the diseases in children, there are all the diseases characteristic of this group, however, unpleasant conditions are also caused by trivial vitamin deficiency.
Helminthic infection, which is more typical for children and adolescents than for adults, can be eliminated by taking anthelmintic drugs, after a course of which the tests return to normal.
Changes in blood during pregnancy
A woman who is pregnant experiences a natural increase in the amount of blood, due to which the hematocrit decreases slightly.
After birth, all indicators return to normal; otherwise, unsatisfactory test results are corrected by taking iron-containing medications.
Extremely low performance lead to malaise and the likelihood of developing anemia. Red blood cell concentrations of less than 30% are dangerous for the unborn baby, since the fetus begins to experience oxygen starvation.
Let's sum it up
Now you know what this means and what the situation leads to when the hematocrit is higher or lower than normal. There are a few basic facts to remember:
- In children, changes in the number of red blood cells are a common physiological norm.
- In newborns, the ratio of elements in the blood is significantly higher than in adults.
- Men have a higher hematocrit value than women.
- A prolonged decrease in red blood cells requires consultation with a hematologist.
- A hematocrit of less than 13% requires urgent hospitalization.
Be attentive to your health! More interesting information on the topic is described in the video:
Today, every person is aware of the existing division of known blood groups according to the ABO system. In biology lessons they talk in some detail about the principles, compatibility, and prevalence of each type among the population. Thus, it is generally accepted that the most rare group blood is the fourth, and the rarest Rh factor is negative. In fact, such information is not true.
Genetic principles
Based on data obtained in the field of archeology and paleontology, geneticists were able to determine that the division into the first occurred more than 40 thousand years ago. It was then, according to scientists, that it arose. Subsequently, over the course of thousands of years, as a result of certain mutational changes, the rest of its types known today arose.
The group affiliation of human blood according to the AB0 system is determined by the presence or absence of unique compounds on the membranes of red blood cells - agglutinogens (antigens) A and B.
Blood type is inherited according to the laws of genetics and is determined by two genes, one of which is passed on to the child by the mother, and the second by the father. Each of these genes is programmed at the DNA level to transmit only one of these agglutinogens or not to contain (and, accordingly, not to transmit in generations) any information (0):
- first 0(I) -00;
- A(II) – A0 or AA;
- B(III) – B0 or BB;
- AB(IV) – AB.
, can be clearly represented in the following examples:
- If parents have groups zero and four, their offspring can inherit only the second or third: AB + 00 = B0 or A0.
- If both parents have group zero, then no other blood group can appear in the offspring: 00 + 00 = 00.
- For parents whose blood types are second and third, children have an equal chance of being born with any of the possible groups: AA/A0 + BB/B0 = AB, A0, B0, 00.
Currently, the existence of the so-called Bombay phenomenon, discovered by scientists in 1952, is known. Its essence lies in the fact that a person’s blood group is determined, which according to the laws of genetics is impossible, what is its explanation and the cause of the effect. That is, there is an agglutinogen on the membranes of his red blood cells, which neither of the parents has.
An example of the Bombay phenomenon, the rarest blood type:
- For parents with group zero, the child is born with group three: 00 + 00 = B0.
- For parents whose groups are zero and , the child is born with the fourth or second: 00 + B0/BB = AB, A0.
After numerous studies, an explanation for the Bombay phenomenon was obtained. The answer is that in extremely rare cases, when blood grouping is determined by standard methods (according to the AB0 system) as zero 0 (I), in fact it is not such. In fact, one of the agglutinogens, either A or B, is present on the membranes of her red blood cells, but under the influence of specific factors they are suppressed and when determining the blood group, the blood behaves as 0 (I). But when a suppressed agglutinogen is inherited in children, it manifests itself. As a result, parents have doubts about the existence of a relationship between them and the child.
How often do such cases occur?
The prevalence of people with the Bombay blood phenomenon in the world does not exceed 0.0004% of all people on the globe. The exception is the Indian city of Mumbai, where the frequency percentage increases to 0.01%. It was by the name of this city that this phenomenon was named (the old name was Bombay).
One of the theories that studies the causes and factors influencing the manifestation of this phenomenon in the population states that among Hindus, a higher frequency of manifestation of this blood type is due to religious characteristics, in particular, the prohibition of eating beef.
In Europe, such a ban does not exist and the frequency of manifestation of Bombay blood in humans here is several times lower. This led geneticists to the idea that beef contains specific antigens that suppress the manifestation of agglutinogens.
Specificity of people's lives
In reality, people with rare Bombay blood are no different from the rest. The only difficulty they may encounter is... Due to the uniqueness of the blood type, they cannot be transfused with any foreign blood, since Bombay blood in humans is incompatible with all other groups. Therefore, people who exhibit this phenomenon are forced to create their own blood bank, which will be used in case of emergency.
In the USA, in the state of Massachusetts, there are currently living a brother and sister who have the manifestation and essence of the Bombay phenomenon. Their blood type is the same, but they cannot donate to each other because their Rh factors are different.
Problems of establishing paternity
When a child is born with manifestations of the Bombay phenomenon, it is impossible to prove its presence without the use of special methods for studying group affiliation. Therefore, the presence of Bombay blood in at least one of the family members (even the most distant relatives) should definitely be taken into account when the father has a desire to establish. Then specialists will conduct a test for genetic matches much more thoroughly and in a more extensive manner; in the process of studying samples of the genetic material of the father and child, the antigenic composition of the blood and the structure of the membranes of erythrocytes will be studied.
It is possible to confirm the manifestation of the Bombay phenomenon in a child only through the use of certain genetic tests, allowing us to establish the type of inheritance of blood group. For this reason, if a child is born with an unexpected blood type, first of all, one should suspect the manifestation of this unusual phenomenon in him, and not suspect the spouse of infidelity. This is the rarest blood group that can occur in humans, but it is extremely rare.
There are three types of genes responsible for blood group - A, B, and 0 (three alleles).
Every person has two blood type genes - one received from the mother (A, B, or 0), and one received from the father (A, B, or 0).
There are 6 possible combinations:
| genes | group |
| 00 | 1 |
| 0A | 2 |
| AA | |
| 0V | 3 |
| BB | |
| AB | 4 |
How it works (from the point of view of cell biochemistry)
On the surface of our red blood cells there are carbohydrates - “H antigens”, also known as “0 antigens”.(On the surface of red blood cells there are glycoproteins that have antigenic properties. They are called agglutinogens.)
Gene A encodes an enzyme that converts some H antigens into A antigens.(Gene A encodes a specific glycosyltransferase that adds an N-acetyl-D-galactosamine residue to an agglutinogen, resulting in agglutinogen A).
The B gene encodes an enzyme that converts some H antigens into B antigens.(Gene B encodes a specific glycosyltransferase that adds a D-galactose residue to an agglutinogen, resulting in agglutinogen B).
Gene 0 does not code for any enzyme.
Depending on the genotype, carbohydrate vegetation on the surface of red blood cells will look like this:
| genes | specific antigens on the surface of red blood cells | blood type | letter designation of the group |
| 00 | - | 1 | 0 |
| A0 | A | 2 | A |
| AA | |||
| B0 | IN | 3 | IN |
| BB | |||
| AB | A and B | 4 | AB |
For example, let’s cross parents with groups 1 and 4 and see why they have a child with group 1.
(Because a child with type 1 (00) should receive a 0 from each parent, but a parent with blood type 4 (AB) does not have a 0.)
Bombay phenomenon
It occurs when a person does not produce the “original” antigen H on his red blood cells. In this case, the person will have neither antigens A nor antigens B, even if the necessary enzymes are present. Well, great and powerful enzymes will come to convert H into A... oops! but there’s nothing to transform, there’s no one!
The original H antigen is encoded by a gene, which is unsurprisingly designated H.
H - gene encoding antigen H
h - recessive gene, H antigen is not formed
Example: a person with the AA genotype must have blood group 2. But if he is AAHh, then his blood type will be the first, because there is nothing to make antigen A from.
This mutation was first discovered in Bombay, hence the name. In India, it occurs in one person in 10,000, in Taiwan - in one in 8,000. In Europe, hh is very rare - in one person in two hundred thousand (0.0005%).
An example of the Bombay phenomenon No. 1: If one parent has the first blood group, and the other has the second, then the child has the fourth group, because neither of the parents has the B gene necessary for group 4.
And now the Bombay phenomenon:
The trick is that the first parent, despite its BB genes, does not have B antigens, because there is nothing to make them from. Therefore, despite the genetic third group, from the point of view of blood transfusion he has the first group.
An example of the Bombay phenomenon No. 2. If both parents have group 4, then they cannot have a child of group 1.
| Parent AB (4 group) |
Parent AB (group 4) | |
| A | IN | |
| A | AA (2nd group) |
AB (4 group) |
| IN | AB (4 group) |
BB (3rd group) |
And now the Bombay phenomenon
| Parent ABHh (4 group) |
Parent ABHh (4th group) | |||
| AH | Ah | B.H. | Bh | |
| A.H. | AAHH (2nd group) |
AAHh (2nd group) |
ABHH (4 group) |
ABHh (4 group) |
| Ah | AAHH (2nd group) |
Ahh (1 group) |
ABHh (4 group) |
АBhh (1 group) |
| B.H. | ABHH (4 group) |
ABHh (4 group) |
BBHH (3rd group) |
BBHh (3rd group) |
| Bh | ABHh (4 group) |
ABhh (1 group) |
ABHh (4 group) |
BBhh (1 group) |
As we see, with the Bombay phenomenon, parents with group 4 can still get a child with group 1.
Cis position A and B
In a person with blood type 4, during crossing over, an error (chromosomal mutation) may occur when both genes A and B appear on one chromosome, but nothing on the other chromosome. Accordingly, the gametes of such an AB will turn out strange: one will contain AB, and the other will have nothing.
| What other parents have to offer | Mutant parent | |
| AB | - | |
| 0 | AB0 (4 group) |
0- (1 group) |
| A | AAV (4 group) |
A- (2nd group) |
| IN | ABB (4 group) |
IN- (3rd group) |
Of course, chromosomes containing AB and chromosomes containing nothing at all will be rejected by natural selection, because they will have difficulty conjugating with normal, non-mutant chromosomes. In addition, AAV and ABB children may experience a gene imbalance (impaired viability, death of the embryo). The probability of encountering a cis-AB mutation is estimated at approximately 0.001% (0.012% cis-AB relative to all AB).
Example of cis-AV. If one parent has group 4, and the other has group 1, then they cannot have children of either group 1 or 4.
And now the mutation:
| Parent 00 (1 group) | AB mutant parent (4 group) |
|||
| AB | - | A | IN | |
| 0 | AB0 (4 group) |
0- (1 group) |
A0 (2nd group) |
B0 (3rd group) |
The probability of having children shaded in gray is, of course, less - 0.001%, as agreed, and the remaining 99.999% falls on groups 2 and 3. But still, these fractions of a percent “should be taken into account during genetic counseling and forensic medical examination.”
Blood is a material that provides the opportunity to study the distribution of peoples without cultural prejudice. This biomaterial is used in various areas Sciences: population genetics, biology and physiology. It is also important that people rarely take blood types into account when choosing partners. Moreover, few people know their own blood type today, and no one tried to find out until 1900.
Red blood cells
Attention! Modern Japan has become an exception due to widespread Japanese stereotypes about people with different types blood. They are playing huge role when choosing marriage partners.
All human populations have the same 29 known blood systems, although they vary in frequency of occurrence in specific groups. Considering the evolutionary proximity of monkeys to our species, we can say that some of them also share a number of identical systems with us.
Before blood transfusion or organ transplantation, the ABO group is identified. It provides 4 types depending on the presence or absence of special agglutinogens on the membranes of red blood cells. Blood type is determined in special laboratories. The information obtained is placed in the patient’s medical record at birth.
What is the AB0 system and why is it used in medicine?
The AB0 system was discovered by Karl Landsteiner at the beginning of the twentieth century. It provides for the separation of groups of biological fluids based on the presence of antigens. In people with the second type, substance A is located on the red blood cell membrane, and in people with the third type, substance B is located. In the fourth type, both antigens are combined, in the first type they are not. Antibodies are always formed against antigens that are not present.
AB0 Unlike other classification systems, antibodies are always present in the ABO system in adults. Sensitization by various bacteria from environment, the membrane inclusions of which are similar to erythrocyte antigens, creates the prerequisites for the formation of antibodies. This occurs from 3 to 6 months of life in infants, whose antibodies are directed against the membrane structures of bacteria.
Since the immune system in this case recognizes the surface structures of microorganisms as specific to the body, it does not form antibodies to them. In the case of blood type A (anti-B), sensitization is confirmed by gram-negative bacteria such as Darmbakterium Escherichia coli. Blood group B (anti-A) includes influenza virus proteins whose epitopes resemble antigen A.
Antibody attack points are determined by the glycosylation of blood proteins and lipids. A carrier of type A blood contains antibodies that recognize and bind to α-galactose in the glycosidic structure of glycoproteins. However, red blood cells of type 0 lack antigen, which does not lead to agglutination and death in groups A and B. This makes carriers of blood group 0 with a negative Rh factor universal donors, that is, their blood can be used for carriers of all other types.
Important! Blood types are determined by allelesA1/A2,B and 0. The product of allele 0 is not detected, this gene is considered “silent” (amorphous). The products of other alleles are antigenic glycoproteins. The gene is located on the long arm of chromosome 9 (9q34).
In addition to antigens A and B, all red blood cells have the so-called heterogeneous substance “H”. It is the precursor substance of A and B. Chemically, the specificity of A is related to α-N-acetyl-D-galactosamine, B-D-galactoside and H-L-fucose. Blood group substances are also found in other biological fluids: saliva, sweat and urine.
Groups are detected using test reagents (with appropriate antibodies):
- Subgroup A1 using anti-A1 serum and anti-A1 phytagglutinins;
- Subgroup A2: indirect detection (since A does not react with anti-A1 serum); B: anti-B serum;
- H-substance is detected by anti-H-phytagglutinins.
Bombay phenomenon
Among tests for rare antibodies, the Bombay type is especially characteristic. Due to a genetic defect, these people lack the H precursor. In this case, no single H allele is dominant. Accordingly, antibodies against H-substance will be formed immune system. Regardless of ABO type inheritance, Bombay type red blood cells do not react with either A or B antibodies (phenotypically 0). The serum reacts with group 0 (phenotypically anti-0). Since the H precursor is present in every AB0 carrier, a person with Bombay phenomenon cannot become a recipient of other blood.
Bombay phenomenon Blood group testing involves regular testing for rare antibodies. Positive result should be noted individually in the clinical history. This patient can only receive his own blood or from other carriers with the same trait. The frequency of anti-H-positive carriers of Bombay blood is 1: 300,000. Bombay phenomenon is a rare group and is unlikely to be transmitted among Europeans, since most of them have dominant H alleles.
Blood type and nationality, race
It is clear that blood group distribution patterns are complex. The strong historical distribution gap indicates a complex history of human evolution. This can be seen using global type 3 blood allele frequency maps.
Allele prevalence table The A blood allele is more common worldwide than the B allele. About 21% of all people have the A allele. The A allele is most common in small, unrelated populations, especially among black Indians (25-30%), Australian Aborigines (many groups make up 35-58%), and the Sami of Northern Scandinavia (45-85%). The allele was apparently absent among Indians living in Central and South America.
Type O blood (resulting from the absence of alleles A and B) is common throughout the world. Up to 63% of people have this blood type. Type 0 is high in frequency among the indigenous populations of Central and South America, where it approaches 100%. It is relatively high among both Aboriginal Australians and Western Europe (especially in populations with Celtic ancestry). The most low frequency 0 – in Eastern Europe and Central Asia, where B blood is more common.
This is interesting! There are truly funny queries related to blood type on the Internet. For example, are negative groups blood characteristic feature race of slaves, or whether nationality can be determined by blood type. Knowledge about blood group and Rh factor is not able to answer such questions.
Which blood type is most common among Russians and Ukrainians?
The first Rh-positive group in Russia is common in 48 percent of people. The second most common group is considered to be Rh-positive. In third place is 3 Rh-positive blood group, which is even less common among Russian and Mongoloid nationalities. The least common is Rh-negative blood.
Among Ukrainians, the most common are the first and second Rhesus-positive blood types. Less than others - the fourth Rh-negative. The average Slav exhibits significant variation relative to groups according to the AB0 system.
What blood type predominates among Jews?
In Israel, there is a predominance of representatives of the second Rh-positive blood. Belonging to the third Rh-negative blood group means that a Jew’s nationality is mixed and diluted with other genes, since this type is extremely rare in the ethnic group. In a typical Jewish family this does not happen often, and the child is usually born with either the second or the first group.
Distribution of Rh factor
Most people in the world have the Rh+ blood type. However, it is more common in some regions. Americans and Aborigines were almost all Rh+ before they started interbreeding with people from other parts of the world.
This does not mean that Americans and Australian Aborigines are historically closely related to each other. Most African populations are about 97-99% Rh+ people. East Asians are 93-99% Rh+. Europeans have the lowest frequency of this type on any continent. They make up 83-85% Rh+. The lowest known frequency is among the Basques of the Pyrenees Mountains between France and Spain. Among them, only 65% of people are Rh positive.
Rh concept The distribution patterns for Diego's system are even more striking. Africans, Europeans, East Indians, Gypsies, Aborigines and Polynesians do not have the Diego antigen. The only populations with Diego antigens are Native Americans (2-46%) and East Asians (3-12%). This non-random distribution pattern is consistent with the hypothesis that Americans are of East Asian origin.
These patterns of blood distribution of types AB0, Rh and Diego are not similar to those related to skin color or other so-called “racial” characteristics. The consequence of this is that specific reasons The categorizations that determine the distribution of human blood types are different from those typically used to categorize people into "races". Since it would be possible to divide humanity into radical different groups, using blood printing in place of other genetically inherited traits such as skin color. There is compelling evidence that the commonly used typological model of race is not scientifically valid.
The more scientists study the precise details of human typology, the more they realize how complex distribution processes are. They cannot be easily generalized or understood. However, this hard-earned scientific knowledge is usually ignored in most countries due to complex social and political problems.
As a result, discrimination based on perceived “racial” groups continues to persist. It's important to keep in mind that this "racial" classification often has more to do with cultural and historical differences than biology. In the real sense, "races" are differences that are created by culture, not biology. This indicates the biological illiteracy of the majority of the population regarding the relatedness of morphological and physiological characteristics ethnic groups.
Ethnos The emergence and origin of human blood groups
Epidemic studies and molecular biology have found that carriers of group 0 have an increased likelihood of survival if infected with malaria (Plasmodium falciparum). This advantage has contributed to the fact that in the humid tropical regions of Africa and the Americas, type zero is more common than in other regions of the world.
According to molecular biology theory, blood type O already arose as a haplogroup from A at least 5 million years ago. What other factors influenced the development and spread various groups blood is still unclear. A closer look at the distribution of blood types and AB0 alleles around the world revealed that group 0 was formed several times, and blood type B recently appeared.
First group When studying allele frequencies, the difference between A in A1 and A2 was first discovered, since A2 antigens are found only a quarter more often than A1 on red blood cells. A recent gene loci sequencing study found six common alleles (A1, A2, B1, O1, O2, O3) and 18 rare variants in German volunteers. Thirteen alleles were found for sequencing loci in Japanese subjects, with the most common alleles being A1 (83%), B1 (97%), O1 (43%), and O2 (53%). A decrease in gene variants is characteristic of the initial effect during migratory movements.
Mongoloids: versions of the origin of group B
Group B is most often found in central Asia and less frequently among indigenous peoples in North and South America and Australia. However, this allele is also common in Africa. In general, in the world, the third group is considered a rare AB0 allele. Only 16% of humanity has it. Identification of blood type and Rh factor: what kind of blood will the child have, table, calculator for determining these indicators Determination of blood group compatibility for conceiving a child, table for determining this indicator, possible risks in case of incompatibility